It is known that the peroxidation of lipids in the living organism is a metal ion catalysed radical process playing an important role in a number of pathological conditions and diseases as well as in ageing. Such diseases and conditions related to the peroxidation of lipids are e.g. the injury of the brain and spinal cord, stroke, certain types of cerebrovascular spasms, tissue damages arising from ischemia (especially the so-called reperfusion injuries occuring during and after restoration of blood flow), furthermore myocardial infarction, atherosclerosis, inflammatory diseases, e.g. rheumatoid arthritis, various autoimmune diseases, drug toxicity, asthma and the like [see e.g. B. Halliwell, FASEB J. 1, 358 (1987) and J. M. C. Gutteridge and B. Halliwell, Methods in Enzymology 186, 1 (1990)].
An intensive research is being carried out worldwide to find on one hand substances which inhibit generally the oxidation processes in the living organism (antioxidants) while on the other hand to discover active agents specifically inhibiting the peroxidation of lipids. Compounds exerting the latter type of activity can be used in mammals, including man, for the prevention and/or treatment of diseases and conditions such as those mentioned above as being related to lipid peroxidation processes. Such drugs may have an outstanding therapeutical importance and active agents that can be used e.g. for the treatment of injuries of the central nervous system can be considered as life-saving medicaments.
Several endogenous substances inhibiting lipid peroxidation are present in the internal regulatory system of the mammalian organism, one of which is .alpha.-tocopherol, i.e. vitamin E [see e.g. M. J. Kelly in "Progress in Medicinal Chemistry" Vol. 25, p. 250, ed.: G. P. Ellis and G. B. West, Elsevier Science Publishers, 1988].